This reducer we use to take our 50mm discharge on a 4700 GPH bushmans bilge pump and we can fit a 40 or 32mm camlock fitting,
reducer colour can vary
Guide for sluice box width and reductions size:
8 inch wide sluice - 32mm reduction and hose
10 inch wide sluice - 40mm reduction and hose
12 inch wide sluice 50mm straight through hose to sluice box